Grinding device for removing weld chill rings from header interiors



Nov. 16, 1954 c. E. ANDERSON 2,694,278 GRINDING DEVICE FOR REMOVING W D CHILL v RINGS FROM HEADER INTER S Filed Aug. 28, 1952 2 Sheets-Sheet 1 INVENTOR C/agncefflyderson ATTORNEY Nov. 16, 1954 c. E. ANDERSON 2,694,278 GRINDING DEVICE FOR REMO c D cam.

RINGS FROM HEADER N ER 5 Filed Aug. 28, 1952 2 Sheets-Sheet 2 23 v F G. 2 22 24 C I a 517062 12 2222022 ATTORNEY United States Patent O GRINDING DEVICE FOR REMOVING WELD CHILL RINGS FROM HEADER INTERIORS Clarence E. Anderson, Wadsworth, Ohio, assignor to The Babcock & Wilcox Company, New York, N. Y., a corporation of New Jersey Application August 28, 1952, Serial No. 306,827

8 Claims. (Cl. 51-245) This invention relates to grinding apparatus and, more particularly, to a grinding apparatus for removing internal annular or circumferential ridges from cylindrical members, such as headers and the like, having a sidewall access opening such as a handhole. -1 Headers and other pressure vessels, particularly in the longer sizes, are frequently fabricated by joining two or more tubular sections in end-to-end relation by circumferential fusion welds between the abutting end faces. To assure a satisfactory joint, the welds must penetrate the full wall thickness of the material of the sections. This usually results in a bead on the inner surface of'the header which desirably must be removed to provide a flush internal surface offering no obstruction to the flow of fluid. When an internal backing ring is used in making the weld, it is fused to the deposited weld metal and must likewise be removed by grinding or other procedure.

When such members are of sufficient diameter, or have access openings sufficiently large, to allow an operator to enter the member, grinding away of the internal ridge or weld backing rings does not present any particular diflieulty. However, when the members are too small in diameter to allow an operator to enter, or when the access openings are too small to receive an operator, grinding away or otherwise removing the weld backing ring is difficult, time consuming, and cumbersome. The operator must reach into the member through the access opening and manually support the grinder while exerting suflicient force to assure effective grinding action.

To avoid the foregoing difiiculties, the present invention is directed to a grinding apparatus which is supported on the outside of a cylindrical member adjacent the access opening, and includes a grinder supporting arm extending through the opening into the member and carrying a grinder at such inner end. More specifically, a projecting bracket or support is clamped against the external surface of the member and carries a rod or shaft which is preferably arranged substantially parallel to the axis of the member. arm is swingably supported by this shaft, for movement in a plane perpendicular to the shaft axis, and this arm extends through the access opening into the member. The inner end of the arm has powered driving means mounted thereon arranged to drive an abrading element, such as a grinding wheel. By suitable manipulation and longitudinal adjustment of the arm, the grinding wheel can be made to grind away successively arcuate segments of the backing ring or ridge.

Preferably, the arm is mounted in a thrust bearing on the outer end of a radial link secured to the support rod or shaft, and is adjustable longitudinally of itself, relative to the thrust bearing, in a plane perpendicular to the axis of the support shaft. Further adjustment is provided by the support shaft being axially adjustable in the support, and preferably biased to a position substantially centered on the support. This allows movement of the grinding wheel transversely of the ridge to assure effective grinding action on relatively wide ridges. As a further feature, the arm is made hollow to form a conduit for the power supply to the grinder motor, the latter preferably being an air motor to which air is supplied from a pressure air conduit connected to the outer end of the arm.

For an understanding of the invention principles, ref erence is made to the following description of a typical 2,694,278 Patented I Nov. 16, 1954 embodiment thereof as illustrated in the accompanying drawings. In the drawings:

Fig. l is a perspective view, partially broken away, of the invention grinding apparatus as mounted on a cylindrical header; and

Fig. 2 is a side elevation view, likewise partially broken away, of the apparatus in position on the header.

Referring to the drawings the invention apparatus ineludes an angular support 10 preferably of inverted V- shape. Support 10, in plan, is in the form of a rectangle having end portions 11, 12 arranged to engage circumferentially spaced zones on the external surface of a tubular member or header 20. Connecting end portions 11 and 12 are leg portions 13 and 14 which, at their apices, form longitudinally spaced bearings 16, 16 for a supported rod or shaft 15. The latter has a collar 17 intermediate i-ts ends engaged by coil springs 18, 18 abutting bearings 16 and normally biasing shaft 15 to a position wherein collar 17 is substantially midway between bearings 16.

The invention apparatus is illustrated as arranged to grind away a backing ring 21 for a fusion weld 22 joining cylindrical sections 23, 24 welded in end abut-ting relation to form member 20. The latter is formed with a wall access opening such as a handhole 25 of insufficient size to permit entry of'an operator into member 20, the latter likewise being of insufficient diameter to permit an operator moving thereinto. In the illustrated and typical practical arrangement, header 20 has an inside diameter of 8" and handhole 25 is 3" in diameter.

Support 10 is clamped firmly in position on the external surface of member'20, with rod 15 extending parallel to the axis of the member and offset from the parallel diameter of handhole 25. Each of the end portions 11, 12 of support 10 carries a projecting lug such as 26, only one of which is shown. A chain 27 has one end secured to the lug 26 not shown in the drawing, extends around member 20, and carries a bolt or screw 28 on its other end which extends through an aperture in the illustrated lug 26. A nut 30 is threaded on the outer end of bolt'28 and, for convenience of manipulation, is provided with a'swinging operating handle 31.

The end of shaft 15 adjacent handhole 25 is threaded, beyond a fixed collar 36, to receive a link 35 extending radially to shaft 15. The outer end of link 35 is apertured to receive a threaded trunnion 41 on a sleeve 40, a nut 42 being provided to clamp link 35 and sleeve 40 together. A thrust bearing 37 is disposed in facing recesses in link 35 and sleeve 40, and a second and smaller thrust bearing 38 is disposed in an outer recess in link 35 and engaged by nut 42. By virtue of the thrust bearings 37 and 38, sleeve 40 is freely oscillatable or rotatable relative to link 35.

An arm 45, preferably in the form of an extra heavy pipe, extends adjustably through sleeve 40, and may be held in adjusted position in the sleeve by set screws 44. Arm 45 extends through handhole 25 into the interior of member 20 and an air cylinder 46 is secured on the inner end of the arm, the interior of arm 45 communicating with the interior of the air cylinder through passages such as 48. A power-vane air motor 47 is operably secured in air cylinder 46 and drives an abrading arrangement, such as grinding wheel 50, engaged with weld backing ring 21. The offset of shaft 15 from the diameter of hole 25 is so adjusted that arm 45 is substantially centered through hole 25.

Air is supplied to drive motor 47 by a suitable pipe (not shown) connected to a source of pressure air and to a reducing coupling 51 connected through a nipple 52 to a globe valve 55. A second nipple 54 connects valve 55 to a street elbow 56 threaded into a reducing coupling 57 threaded into the outer end of arm 45.

To grind away ring 21, support 10 is adjusted along member 20 until, with rod 15 centered relative to bearings 16, grinding wheel 50 is aligned with ring 21. Handle 31 is then manipulated to rotate nut 30 and draw up bolt or screw 28 to tighten chain 27 around member 20. Set screws 44 are loosened and arm 45 is adjusted longitudinally of itself until wheel 50 is engaged with ring 21. Motor 47 is then energized by opening valve 55 and arm 45 is oscillated to move grinding wheel 50 over a small arc of ring '21. When this small arc has been ground flush with the inner surface'of member 20, arm 45 is again adjusted in sleeve or slide 40 to engage wheel 50 with an adjacent segment or are of ring 21. This process is repeatedmntil t'h'e entire ring 21 has been ground away. The springs 18 :bias shatt IE to a position where grindin'gswheel 50 :is centered on ring 21. However, the springs allow reciprocation of shaft 15 so that wheel 50 can be moved transversely of ring 21 in the event the ringv is equal to or greater in Width than the grinding wheel, and also to assure effective removal of the fiullwidth of ring 21.

In the "illustrated ease, support is shown as arranged for removing a weld backing ring lying in a diameter plane or one perpendicular to the axis of member 20, the lengths of legs-13,- 14, extending from their apices, being equal to each other. The described apparatus is light weight and portable, easily mounted in position, easily adjusted, and so arranged that grinding wheel 50 may be engaged yith any part of the circumferential extentof the ridge or backing ring 21. In mounting the apparatus, the motor 47 and associated parts is first inserted through handhole 25, after which support 10 is clamped in position and the air line secured to reducer- 5 1.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the invention principles, it will be understood that the inyention maybe embodied otherwise without departing from 'such principles.

whatisclaimed'isz p g l. A grinder for removing internal annular ridges or Weld backing rings from cylindrical members having a side wall access opening, said grinder comprising, in combination .a support including a pair of divergent legs having outer parallel rectilinear edges arranged to engage the external surface of a cylindrical member along circumferentially spaced zones and shaft bearing means interconnecting theinner edges of said legs and having an axis parallel to such outer edges; clamping means connecting the outer edges of said legs and arranged to embrace the cylindrical member to secure said support on the member adjacent the access opening in the latter; a shaft mounted in said bearing means, said shaft being oscillatable about its own axis; a link extending radially from an end of said shaft; an arm 'sWinga-bly supported on the free end of said link for swinging movement in a plane perpendicular to the shaft axis and adjustable longitudinally of itself in said plane; said arm being adapted to extend through the access opening into the member; powered driving means mounted on 'the' 'end of said arm extendable within the member; and an abrading element driven by said driving means and engageable with such internal ridge or ring by movement of said arm relative to said support.

2. A grinder as claimed in claim 1 in which said shaft extends substantially parallel 'to the axis of the member and is axially adjustable relative to said support.

3. A grinder as claimed in claim 1 in which said shaft is axially adjustable relative to said support; and means biasing said shaft to a position substantially centred lengthwise in said support.

4. A grinder as claimed in claim 1 including a thrust bearing in the free end of said link, said arm being mounted in said thrust bearing.

5. A grinder as claimed in claim 1 in Which said arm forms a conduit for the power supply to said driving means.

6. -A grinder as claimed in claim 1 in which said driving means comprises an air powered motor.

7. A grinder as claimed in claim 1 in which said driving means comprises an air powered mo'tor; and including a thrust bearing in the free end of said link,- s'aitl arm being mounted in said thrust bearing.

87 A grinder as claimed in claim l in which said driving means comprises an air powered motor and said arm forms a conduit for the air supply to said motor; and a source 'of pressure air connected to the outer end of said arm.

References Cited in the file of this patent STATES PATENTS 

